1. Field of the Invention
The present invention is for hydraulic ejection of stores from aircraft. In particular, the present invention is for the release of stores via hydraulic pistons which extend upon release of pressure.
2. Description of the Prior Art
Numerous aircraft store ejection mechanisms are known. Modern high speed aircraft now use ejection racks powered by pyrotechnic cartridges. The pyrotechnic cartridge provides a predictable large overpressure which provides sufficient pressure to drive piston release mechanisms. The release of stores from high speed aircraft ideally should be done when the store is as far from the aircraft as is practical. This is at odds with the carried configuration of the store where, for aerodynamic purposes, the store is desired to be as close to the aircraft and, if possible, molded into the overall airframe configuration. The release of stores, such as missiles or bombs, close to the airframe permits turbulence to bounce the released store into the aircraft causing structural damage. Thus, modern stores on high speed aircraft are ejected from the aircraft to ensure a safe separation distance when the store enters free flight.
The use of pyrotechnic cartridges provides adequate power to ejector pistons but is unpredictable and cannot be varied in the light of special conditions. The use of pyrotechnics required frequent cleaning of the ejection racks and a new cartridge to be used after each firing. A further complication of such release mechanisms is that fail safe devices are harder to control. The actual pressure in the cartridge only occurs at maximum value when the store is to be ejected. Ideally, if there is going to be a pressure failure in the piston, the pilot of the aircraft would like to know this fact prior to committing an attempted launch of the store. This capability reduces the number of hung stores that could occur on an aircraft in flight.